The Theosophical Society is an organization formed in New York City on November 17, 1875, by a committee of people including Russian noblewoman Helena Petrovna Blavatsky, American Colonel Henry Steel Olcott, American attorney William Quan Judge, and other individuals interested in the philosophy expounded by Madame Blavatsky.
In her Theosophical Glossary, H. P. Blavatsky wrote:
Theosophical Society, or “Universal Brotherhood”. Founded in 1875 at New York, by Colonel H. S. Olcott and H. P. Blavatsky, helped by W. Q. Judge and several others. Its avowed object was at first the scientific investigation of psychic or so-called “spiritualistic” phenomena, after which its three chief objects were declared, namely (1) Brotherhood of man, without distinction of race, colour, religion, or social position; (2) the serious study of the ancient world-religions for purposes of comparison and the selection therefrom of universal ethics; (3) the study and development of the latent divine powers in man. At the present moment it has over 250 Branches scattered all over the world, most of which are in India, where also its chief Headquarters are established. It is composed of several large Sections—the Indian, the American, the Australian, and the European Sections.
In 1881 she wrote:
The Theosophical Society teaches no new religion, aims to destroy no old one, promulgates no creed of its own, follows no religious leader, and, distinctly and emphatically, is not a sect, nor ever was one. It admits worthy people of any religion to membership, on the condition of mutual tolerance and mutual help to discover truth. The Founders have never consented to be taken as religious leaders, they repudiate any such idea, and they have not taken and will not take disciples. 
On Tuesday, September 7, 1875, a meeting was organized at Mme. Blavatsky's rooms to hear a lecture given by George H. Felt entitled "The Lost Canon of Proportion of the Egyptians, Greeks and Romans". About 17 people were present. During the discussion that followed the lecture, a suggestion was made that a Society be formed to pursue and promote such occult research.
On the next day another meeting took place with Mr. Felt lecturing again. The Society was more definitely organized and sixteen people handed in their names for that purpose. A committee of three was appointed to draft a Constitution and Bylaws.
On September 13, in a new meeting at the same address, Mr. Felt gave another lecture. At this time the name of "The Theosophical Society" was agreed upon.
According to Col. Olcott, the choice of the name of the newly formed Society was subject of discussion in the committee, and several options were suggested, such as the Egyptological, the Hermetic, the Rosicrucian, etc. However, none of them seemed the right one. ‘At last,’ he recalls ‘in turning over the leaves of the Dictionary, one of us came across the word “Theosophy,” whereupon, after discussion, we unanimously agreed that that was the best of all.’ Olcott explained this name was appropriate because it expressed ‘the esoteric truth we wished to reach’ and covered the ground of ‘methods of occult scientific research.’
It does not seem likely that the name for the Society was chosen merely out of a dictionary search, since Madame Blavatsky had already connected her knowledge with the term theosophy a few months before, in a letter to Hiram Corson:
My belief is based on something older than the Rochester knockings [that began the Spiritualistic movement in 1848], and springs out from the same source of information that was used by Raymond Lully, Picus della Mirandola, Cornelius Agrippa, Robert Fludd, Henry More, et cetera, etc., all of whom have ever been searching for a system that should disclose to them the "deepest depths" of the Divine nature, and show them the real tie which binds all things together. I found at last, and many years ago, the cravings of my mind satisfied by this theosophy taught by the Angels and communicated by them.
On October 16 and October 30, two preliminary meetings are held in the drawing-rooms of Mrs. Emma Hardinge Britten, 206 West 38th Street, New York to approve the Bylaws and elect the officers. The Mott Memorial Hall, 64 Madison Avenue, New York, was selected as the Society’s meeting place.
See also Founding of the Theosophical Society
Origin, Plan and Aims
Henry Steel Olcott drew up a circular entitled "The Theosophical Society: Its Origin, Plan and Aims," which was made available for distribution on May 3rd, 1878. In it, he outlined the organization, offices, and membership of the organization.
Move to India
In 1879, Mme Blavatsky and Col Olcott, moved to India, where the Society spread rapidly. In 1882, they established the Society's International Headquarters in Adyar, a suburb of Madras (currently Chennai), where it has since remained. They also visited Sri Lanka, where Olcott was so active in promoting social welfare among oppressed Buddhists that even now he is a national hero of that land.
Theosophical Societies in the world
Below are listed, in alphabetical order, the different organizations using the name "Theosophical Society". For information about other Theosophical organizations see article on the Theosophical Movement.
The Objects of the Theosophical Society have undergone a gradual development until they reached their current form by the end of the 19th century.
The Theosophical Society (Adyar) states its Objects as follows:
1. To form a nucleus of the Universal Brotherhood of Humanity, without distinction of race, creed, sex, caste or colour.
2. To encourage the study of comparative religion, philosophy and science.
3. To investigate unexplained laws of Nature and the powers latent in man.
The Theosophical Society (Pasadena) has the following Objectives, as stated in its constitution:
1- To diffuse among men a knowledge of the laws inherent in the universe;
2- To promulgate the knowledge of the essential unity of all that is, and to demonstrate that this unity is fundamental in nature;
3- To form an active brotherhood among men;
4- To study ancient and modern religion, science, and philosophy;
5- To investigate the powers innate in man.
- Why One Should Join The Theosophical Society by "B.K."
- "Family Tree" of the Theosophical Movement by Dorothy Bell
- The New Cycle by H. P. Blavatsky
- The Original Programme of The Theosophical Society by H. P. Blavatsky
- The Organisation of the Theosophical Society by H. P. Blavatsky
- The Theosophical Society: Its Mission and Its Future by H. P. Blavatsky
- The Founding of the Theosophical Society by Walter A. Carrithers, Jr.
- From the Archives: Passage to India: A Mission from the Masters by Paula Chernyshev Finnegan
- Famous People and the Impact of the Theosophical Society Compiled by Katinka Hesselink
- Public Speeches at the Second Annual Convention of the European Section of the Theosophical Society by W.Q. Judge, G.R.S. Mead, Count Leiningen, H. Burrows, and A. Besant
- The Future and the Theosophical Society by William Q. Judge
- Methods of Theosophical Work by William Q. Judge
- The Promulgation of Theosophy by William Q. Judge
- Theosophical Study and Work by William Q. Judge
- The Backgroung to the Founding of the Theosophical Society by Geoffrey Farthing
- Psychic Phenomena and the Early Theosophical Society by Pablo Sender
- A Historical Look at the Theosophical Movement by John Cooper
- Chaos, Plan, and Order in the Society's History by John Algeo
- The Dawning of the Theosophical Age by Michael Gomes
- Manifest Destiny: Theosophical History as Spiritual Narrative by Michael Gomes
- Blavatsky, H. P., Theosophical Glossary (Krotona, CA: Theosophical Publishing House, 1918), 304.
- Helena Petrovna Blavatsky, Collected Writings vol. III (Wheaton, IL: Theosophical Publishing House, 1995), 4.
- Olcott, H. S., Old Diary Leaves, v. 1 (Adyar, Madras: Theosophical Publishing House, 1974), 132
- Algeo, John (Ed.), The Letters of H. P. Blavatsky, v. 1, Letter 21, (Wheaton, Il: Quest Books, Theosophical Publishing House, 2003), 86.
- "The Theosophical Society: Its Origin, Plan and Aims," Theosophical University Press Online
- Ransom, J. A Short History of the Theosophical Society (Adyar, Madras, India: Theosophical Publishing House, 1950), ??.